1. Technical Field
The invention relates to an improved coupler for a piping system. More particularly, the invention relates to a coupler for a low pressure or vacuum piping system for transporting materials with air. Specifically, the invention relates to a coupler generally made of a hollow metal tube and configured to receive another metal tube and clamp down on the other tube to create metal to metal contact between the two tubes and a seal between the tubes, and to an improved annular seal inserted in the hollow metal tube.
2. Background Information
In the past, vacuum and pressure pipes which were used for transporting material, such as tobacco or fine dust from wood shops or flour mills, etc. have been held together with coupling systems. However, such dust has a tendency to explode. Therefore, metal straps have been used in couplings having rubber gaskets to assure that metal to metal contact exists for grounding. These metal straps add cost to the coupler and can also push seals out of place during installation. Thus, there exists a need to maintain metal to metal contact between a coupler and the joined piping without the need for separate metal grounding straps.
In high vibration areas, piping can vibrate out of a coupling, breaching the system. Thus, creating a strong clamping bond between the coupler and piping in the system is of primary concern.
In addition, a reliable and airtight seal is required under low pressure or vacuum conditions to ensure that the material flowing through the pipes does not leak out and that an effective and efficient flow is maintained. Thus, the creation of an airtight seal is important.
Also, there is a need for a coupler that is easily and quickly installed, and which reduces or eliminates the need for training for installing the coupler.
Thus, the need exists for a coupler for a low pressure piping system that is easy to install, which will maintain metal to metal contact throughout the system without the use of metal straps, which will remain intact in high vibration areas, and which will maintain an airtight seal under low pressure conditions.